Method and apparatus for polymer application to intracorporeal device

ABSTRACT

A method and apparatus for applying a polymer coating on an elongated substrate, preferably an elongate intracorporeal device in the form of a guidewire. An extrudable polymer cartridge is moved by a cartridge advancement mechanism into a guide chamber which is heated at an end with a die or orifice through which a desired portion of a guidewire may pass and be coated. Parameters such as guide chamber temperature, pull speed and force exerted by the cartridge advancement mechanism may be controlled with a computer program in order to achieve repeatable results. The guide chamber, extrudable polymer cartridge, die, and push tube may all be made from polymer components which can be reused or disposed of after a single use. The extrudable polymer cartridge may have a variety of configurations including multiple layers of different materials, eccentric shapes, multiple lumens for multiple elements to be drawn through and coated and asymmetric disposition of different materials with respect to the longitudinal axis as viewed in a transverse cross section which can give bending properties having a preferred direction in the coated guidewire or device.

BACKGROUND

[0001] This invention relates to an apparatus and method for applying apolymer coating to a desired length of an elongate member, preferably toan elongate intracorporeal device. More specifically, the inventionrelates to a method and apparatus for applying a polymer coating to adesired length of an intracorporeal guiding device or guidewire. Theinvention can also be used to apply a polymer coating to a length of anyother suitable device such as a vascular stent, cardiac pacing leads,catheter tubings, braided or solid electrical wire, coaxial cable or thelike.

[0002] In a typical prior art process for applying a polymer coatingover an elongate member, an extrusion machine is used which has a heateddie head with channels leading to a heated chamber within the die head.Melted polymer is forced into the chamber with a lead screw which forcessolid polymer, usually in the form of pellets, into the heated chamber.The elongate member to be coated is passed through the back end of thedie head into the chamber and out of an orifice in an extrusion diewhich is attached to the extrusion head. The elongate member is thenpulled through the die as melted polymer is forced into the die head andonto the elongate member. Normally, the orifice in the die will belarger than the elongate member so that a desired amount of the meltedpolymer remains on the elongate member after passing through theorifice. After passing through the orifice, the melted polymer on theelongate device cools and the coating process is complete.

[0003] A prior art process such as that described above is well suitedin many cases for coating long lengths of durable elongated members orsubstrate. The equipment used is large, expensive and cumbersome and candamage a fragile substrate being pulled through the device, such as aguidewire distal section with a small diameter helical coil. Inaddition, the amount of effort and expense required for a given set upoften does not justify small runs of material. Also, the equipment isnot Nell suited for coating short lengths of discrete elongated members,such as guidewires or the like, because adjusting the settings toachieve desired coating dimensions and parameters is usually a processthat requires several minutes of running time in order for equilibriumof the dynamic to be established and stabilization of the process tooccur. This often requires running many feet of substrate through thedie head prior to stabilization which is not possible with a guidewirewhich is only several feet long.

[0004] Another difficulty exists in trying to vary the coatingparameters dynamically in a controlled fashion in order to achieve acoating which has varying parameters such as a transverse dimensionalong an axial direction. As mentioned above, the usual coatingequipment of the prior art is large and cumbersome and it is impracticalto vary parameters such as temperature of the die, speed of pull, andpressure exerted on the melted polymer over short lengths of an elongatemember substrate.

[0005] What has been needed is an apparatus suitable for applying avariety of polymer coatings to a discrete length of a fragileintracorporeal device substrate with quick response time for variationin extrusion parameters. What has also been needed is an apparatussuitable for coating an elongate intracorporeal member that hasautomatable control of extrusion parameters such as die temperature,pull speed and pressure applied to melted polymer which can producerepeatable control of diameter and other dimensions of the polymercoating applied. In addition, it is desirable to have an apparatussuitable for reliably applying a polymer coating with a constant outertransverse dimension to a substrate which varies in transverse dimensionor diameter along its axial length.

SUMMARY

[0006] The invention is directed to an apparatus for applying a polymercoating to an elongate intracorporeal device, specifically, a guidewire.In one embodiment, the apparatus can have a guide chamber with an inputend having an input port and an output end. An extrusion orifice isdisposed at the output end of the guide chamber and is in fluidcommunication with the guide chamber. The extrusion orifice can beconfigured to allow an elongate intracorporeal device or other substrateto pass through or be pulled through the extrusion orifice with adesired thickness or configuration of polymer coating on the elongateintracorporeal device or substrate. The orifice can be configured toleave a fixed thickness of polymer over the elongate intracorporealdevice, or the orifice can be shaped so as to leave a desired profile orconfiguration of polymer coating on the device, e.g., an orifice havingan oval, square or triangular cross section.

[0007] A heater member is disposed in thermal communication with theguide chamber and serves to heat a desired portion of the guide chamber.A cartridge advancement mechanism is disposed adjacent the guidechamber. In use, an extrudable polymer cartridge is placed within theguide chamber of the apparatus. The cartridge advancement mechanism canbe configured to axially translate the extrudable polymer cartridge intothe guide chamber in a direction of extrusion, i.e., a direction fromthe input end of the guide chamber to the output end of the guidechamber. The extrudable polymer cartridge can have a lumen extendinglongitudinally through the cartridge with the lumen being sized orconfigured to accept the elongate intracorporeal device. The lumen ofthe extrudable polymer cartridge is typically sized to allow theelongate intracorporeal member to slide freely within the lumen.

[0008] In another embodiment, a guide chamber is formed by a guide tubewith the guide chamber being disposed within the guide tube. The guidetube has an input end with an input port in fluid communication with theguide chamber and an output end. A die having an extrusion orifice isdisposed at the output end of the guide tube such that the extrusionorifice is in fluid communication with the guide chamber. The extrusionorifice of the die can be configured to allow an elongate intracorporealdevice to pass through the die with a desired configuration of polymercoating on the member. A heater member is disposed in thermalcommunication with the guide tube for heating a desired portion of theguide tube or die.

[0009] A push tube is disposed at least partially and slidably withinthe guide chamber. The push tube has a contact end, an attachment end, alongitudinal axis and at least one inner lumen extending substantiallyparallel to the longitudinal axis of the push tube. The inner lumen ofthe push tube is configured to accept a desired elongate intracorporealdevice. In use, an extrudable polymer cartridge, having similarproperties to the extrudable polymer cartridge discussed above, can bedisposed within the guide chamber between the extrusion orifice of thedie and the contact end of the push tube.

[0010] In another embodiment, a puller is disposed adjacent the outputend of the guide tube. The puller can be configured to be temporarilysecured to a desired portion of the elongate intracorporeal device andapply a force and movement in the direction of extrusion on the device.A push tube actuator is disposed adjacent the input end of the guidetube and is configured to apply a force and movement on the extrudablepolymer cartridge disposed within the guide chamber. Specifically, thepush tube is disposed between the extrudable polymer cartridge and thepush tube actuator and mechanically couples the push tube actuator tothe extrudable polymer cartridge. A computing machine may beelectronically connected to a temperature sensor coupled to the heatermember, the puller and the push tube actuator. The computing machine canbe used to repeatably control the temperature of the heating member, therate of axial movement of the elongate intracorporeal device in adirection of extrusion by controlling the rate of axial movement of thepuller, and the rate of feed or axial movement in the direction ofextrusion of the extrudable polymer cartridge by controlling the rate ofmovement or force applied to the push tube in the direction ofextrusion.

[0011] One of the advantages of the apparatus for applying a polymercoating is that many of the components of the apparatus can bemanufactured from disposable polymer materials that are made to bemodular and avoid the need for cleaning of components. For example, boththe guide tube and the die can be made from a variety of hightemperature polymers such as polyimide (PI), polytetraflouroethylene(PTFE), liquid crystal polymer (LCP) and polyetheretherkeytone (PEEK)This allows a subassembly consisting of the guide tube, die andextrudable polymer cartridge to be loaded into a corresponding guidetube assembly for each elongate intracorporeal device to be coated. Whenthe device has been coated, the subassembly can be disposed of and a newsubassembly loaded into the guide tube assembly. This eliminates theneed for time consuming cleaning operations and allows the use ofvarying die configurations and extrudable polymer cartridge materialsfrom one elongate intracorporeal device to the next.

[0012] Another advantage of the apparatus for applying a polymer coatingis the ability to reliably maintain concentricity of the coating appliedto the elongate inctracorporeal device. Where such concentricity isdesired, the use of an extrudable polymer cartridge having an innerlumen which is concentric to a longitudinal axis of the cartridgeprovides centering of the elongate intracorporeal device prior topassing through the extrusion orifice. As the extrudable polymercartridge is melted at the output end of the guide chamber and appliedto the elongate intracorporeal device, the unmelted portion of thecartridge immediately adjacent a melt zone of the extrudable polymercartridge continuously provides centering of the elongate intracorporealdevice within the guide chamber and extrusion orifice. Also, the meltedportion of the extrudable polymer cartridge at the melt zone can beapplied evenly in a radially inward direction from all sides of theelongate intracorporeal device in embodiments of the invention where theinner lumen of the extrudable polymer cartridge is concentric with thelongitudinal axis of the cartridge. This can also facilitate maintainingconcentricity of the polymer coating.

[0013] In use, an extrudable polymer cartridge is placed in the guidechamber of the guide tube between the extrusion orifice and the contactend of the push tube. An elongate intracorporeal device is loaded intothe die, at least of a portion of the inner lumen of the extrudablepolymer cartridge and optionally the inner lumen of the push tube. Theelongate intracorporeal device is then temporarily secured to the pullerand the heater member activated. When the portion of the extrudablepolymer cartridge adjacent the die attains a desired temperature andviscosity, the puller and cartridge advancement mechanism, typicallyconsisting of a push tube actuator, are activated. This advances boththe elongate intracorporeal device and extrudable polymer cartridge inthe direction of extrusion, i.e. in a direction from the input end ofthe guide chamber to the output end of the guide chamber.

[0014] The coating process can be terminated in several ways. Theprocess may be terminated when an end or extremity of the elongateintracorporeal device is drawn through the output end of the guidechamber and die. This method will typically coat the entire end orextremity of the elongate intracorporeal device. Alternatively, theadvancement of the extrudable polymer cartridge can be stopped bydeactivating the cartridge advancement mechanism while continuing toadvance the elongate intracorporeal device in the direction ofextrusion. In this way, the melted extrudable polymer cartridge is nolonger feeding into the extrusion orifice and coating the elongateintracorporeal device. Also, the amount of material in the extrudablepolymer cartridge may be limited to suffice for coating only a desiredportion of an elongate intracorporeal device. As the extrudable polymercartridge is advanced in the direction of extrusion and polymer coatingis applied, the cartridge gets shorter. The process continues until thecontact end of the push tube hits the die and melted polymer material isno longer fed into the extrusion orifice and the coating process stops,although the elongate intracorporeal may continue to be pulled oradvanced in the direction of extrusion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is an elevational view in partial section of an apparatusfor applying a polymer coating to an elongate intracorporeal devicehaving features of the invention.

[0016]FIG. 2 is an elevational view in partial section of the guide tubeassembly shown in FIG. 1 taken along lines 2-2 in FIG. 1.

[0017]FIG. 3 is a transverse cross sectional view of the guide tubeassembly shown in FIG. 2 taken along lines 3-3 in FIG. 2.

[0018]FIG. 4 is a transverse cross sectional view of the guide tubeassembly shown in FIG. 2 taken along lines 4-4 in FIG. 2.

[0019]FIG. 5 is an elevational view in longitudinal cross section of thedie in the guide tube assembly shown in FIGS. 1-4, having features ofthe invention

[0020] FIGS. 6A-6C are transverse cross sectional views of the die shownin FIG. 5 taken along lines 6-6 in FIG. 5, having various extrusionorifice configurations.

[0021]FIG. 7 is an elevational view in partial section of a tandemapparatus for applying a polymer coating to an elongate intracorporealdevice having features of the invention.

[0022]FIG. 8 illustrates an elevational view in section of a guide tubeassembly having features of the invention.

[0023]FIG. 9 is a transverse cross sectional view of the guide tubeassembly of FIG. 8 taken along lines 9-9 in FIG. 8.

[0024]FIG. 10 illustrates an extrudable polymer cartridge havingfeatures of the invention.

[0025]FIG. 11 is a transverse cross sectional view of the extrudablepolymer cartridge of FIG. 10 taken along lines 11-11 in FIG. 10.

[0026]FIG. 12 illustrates an extrudable polymer cartridge havingfeatures of the invention.

[0027]FIG. 13 is a transverse cross sectional view of the extrudablepolymer cartridge of FIG. 12 taken along lines 13-13 in FIG. 12.

[0028]FIG. 14 illustrates an extrudable polymer cartridge havingfeatures of the invention

[0029]FIG. 15 is a transverse cross sectional view of the extrudablepolymer cartridge of FIG. 14 taken along lines 15-15 in FIG. 14.

[0030]FIG. 16 illustrates an extrudable polymer cartridge havingfeatures of the invention.

[0031]FIG. 17 is a transverse cross sectional view of the extrudablepolymer cartridge of FIG. 16 taken along lines 17-17 in FIG. 16.

[0032]FIG. 18 illustrates an extrudable polymer cartridge havingfeatures of the invention.

[0033]FIG. 19 is a transverse cross sectional view of the extrudablepolymer cartridge of FIG. 18 taken along lines 19-19 in FIG. 18.

DETAILED DESCRIPTION

[0034] FIGS. 1-4 illustrate a polymer coating apparatus 10 for applyinga polymer coating 11 to an elongate intracorporeal device 12. A guidetube assembly 13 is removably secured to a guide tube assembly mount 14.The guide tube assembly mount 14 is secured to a mounting surface 15,which can be an even vertical surface, but which can have any desiredconfiguration or orientation. A heater member 16 is secured in thermalcommunication with a guide tube housing 17 of the guide tube assembly 13and serves to supply heat energy to a desired portion of the guide tubeassembly 13. The guide tube assembly 13 includes a guide tube housing 17which has an input end 18 and an output end 19. The output end 19 has athreaded portion 22 and the input end 18 has a retainer lip 23. Aretainer cap 24 is threaded onto the threaded portion 22 of the outputend 19 of the guide tube housing 17.

[0035] The guide tube housing 17 can be made of a conductive materialsuch as stainless steel, a machineable insulative material such asVespel® or any other suitable material. A guide tube 25 having an inputend 26 , an output end 27 and a guide chamber 28 disposed within theguide tube 25 is disposed within the guide tube housing 17. The inputend 26 of the guide tube 25 is disposed against the retainer lip 23 ofthe guide tube housing 17. A die 31 having an input end 32 and an outputend 33 is disposed within the guide tube housing 17 with the input end32 of the die 31 against the output end 27 of the guide tube 25. Anoptional centering insert 34 having an input end 35 and an output end 36is disposed within the guide tube housing 17 with the input end 35 ofthe centering insert 34 against the output end 33 of the die 31. Theretainer cap 24 with a center hole 37 is threaded onto the threadedportion 22 of the guide tube housing 17 to hold the guide tube 25, dieand centering insert 34 within the guide tube housing 17.

[0036] In one embodiment, the guide tube 25 has a length of about 0.5 toabout 5 inch, specifically about 1.0 to about 3.0 inch. The guide tube25, die 31 and centering insert 34 can have an outer diameter of about0.03 to about 0.2 inch, specifically about 0.05 to about 0.1 inch. Theguide tube 25 of the embodiment can have a wall thickness of about 0.005to about 0.015 inch. In other embodiments, the length, outer diameterand wall thickness of the guide tube 25 can vary significantly from thedimensions given above to suit the desired application. The guide tube25, die 31 and centering insert 34 can be disposable and made from ahigh temperature polymer such as PI, PTFE, LCP or PEEK.

[0037] As best shown in FIG. 1, a puller 40 is disposed adjacent anoutput end 41 of the guide tube assembly 13 and has a clamp 42 alignedwith the longitudinal axis 43 of an inner lumen 44 of the die 31 fortemporarily securing the elongate intracorporeal device 12 to the puller40. The clamp 42 temporarily secures a desired portion of the elongateintracorporeal device 12 to the puller 40 such that the elongateintracorporeal device 12 is centered within the inner lumen 44 of thedie 31. The puller 40 is slidably disposed on a puller track 45 and hasmotor 46 which mechanically engages the puller track 45 and moves thepuller 40 parallel to a longitudinal axis 47 of the guide tube assembly13.

[0038] A cartridge advancement mechanism 51 consisting of a push tubeactuator 52 and a push tube 53 is disposed adjacent an input end 54 ofthe guide tube assembly 13. The push tube actuator 52 is mechanicallycoupled to the push tube 53 with the push tube 53 having a contact end55 and an actuator end 56. The push tube 53 is configured to have thecontact end 55 slidably disposed within the guide chamber 28 of theguide tube 25 and apply force to an extrudable polymer cartridge 57disposed within the guide chamber 28 in a direction of extrusion. Thedirection of extrusion is defined to be from the input end 54 of theguide tube assembly 13 to the output end 41 of the guide tube assembly13 as indicated by arrows 58.

[0039] The push tube actuator 52 is slidably disposed on a push tubeactuator track 61 such that a longitudinal axis 62 of an inner lumen 63of the push tube 53 is aligned with the longitudinal axis 43 of the die31 and longitudinal axis 64 of an inner lumen 65 of the extrudablepolymer cartridge 57. A push tube actuator motor 66 is disposed on thepush tube actuator 52 and mechanically coupled to the push tube actuatortrack 61 so as to enable the motor 66 to axially translate the push tubeactuator 52 on the push tube actuator track 61 along a longitudinal axis47 of the guide tube assembly 13.

[0040] The elongate intracorporeal device 12 is disposed within an innerlumen 67 of the centering insert 34, the extrusion orifice 68 of the die31, the inner lumen 65 of the extrudable polymer cartridge 57 and theinner lumen 63 of the push tube 53. The elongate intracorporeal device12 is also shown as being disposed along the longitudinal axis 47 of theguide tube assembly 13. Other configurations may be used where theelongate intracorporeal device 12 is offset from the longitudinal axis47 of the guide tube assembly 13.

[0041] A computer 71 is in electrical communication with an electroniccontrol unit 72 which is in electrical communication with a temperaturesensor 73 disposed in thermal communication with the heater member 16, apuller position indicator 74 disposed on the puller 40, and a push tubeactuator position indicator 75 disposed on the push tube actuator 52.The temperature sensor 73 provides an electrical signal to the computer71 indicating the temperature of the heater member 16. The pullerposition indicator 74 provides an electrical signal to the computer 71indicating the position of the puller 40 relative to the output end 41of the guide tube assembly 13. The push tube actuator position indicator75 provides an electrical signal to the computer 71 indicating theposition of the push tube actuator 52 relative to the input end 54 ofthe guide tube assembly 13. In addition, the computer 71 is electricallycoupled to the control unit 72 such that a signal from the computer 71can control the amount of power to the heater member 16, the speed anddirection of translation of the puller 40 and the speed and direction oftranslation of the push tube actuator 52.

[0042] In this way, the computer 71 can be programmed to repeatablycontrol the temperature of the heater member 16, the rate of pull of theelongate intracorporeal device 12 through the guide tube assembly 13 andthe rate of feed of the extrudable polymer cartridge 57 into the guidechamber 28 in the direction of extrusion. This enables the computer 71to repeatably control the entire coating process for consistent coatingresults. The computer 71 may be a standard personal computer, or anysuitable substitute such as a custom integrated circuit or the like. Inaddition, the function of the computer 71 could be carried out withstandard analog circuitry of suitable configuration that would provide adesired and repeatable heater member 16 temperature, rate of pull of thepuller 40 and rate of feed of the push tube actuator 52.

[0043] In use, the retainer cap 24 is removed from the guide tubehousing 17. The guide tube 25 is loaded into the guide tube housing 17from the output end 19 of the guide tube housing 17 until the input end26 of the guide tube 25 contacts the retainer lip 23 of the guide tubehousing 17 and the contact end 55 of the push tube 53 enters the guidetube chamber 28 at the input end of the guide tube 25. The extrudablepolymer cartridge 57 is then loaded into the guide chamber 28 at theoutput end of the guide tube 25 until it contacts the contact end 55 ofthe push tube 53. Next, the die 31 is loaded into the guide tube housing17 with the input end 32 of the die 31 adjacent the output end 27 of theguide tube 25. The centering insert 34 is then loaded into the guidetube housing 17 with the input end 35 of the centering insert 34adjacent the output end 33 of the die 31. The retainer cap 24 is thenreplaced which confines the guide tube 25, extrudable polymer cartridge57, die 31 and centering insert 34 within the guide tube housing 17.

[0044] The elongate intracorporeal device 12 is then inserted throughthe inner lumen 67 of the centering insert 34, the extrusion orifice 68and inner lumen 44 of the die, the inner lumen 65 of the extrudablepolymer cartridge 57, and at least a portion of the inner lumen 63 ofthe push tube 53. The elongate intracorporeal device 12 is thentemporarily secured to the puller 40 by the clamp 42. The coating cycleis then started by supplying power to the heater member 16 which heats adesired portion of the die 31, guide tube 25 and extrudable polymercartridge 57 which are adjacent and in thermal communication with theheater member 16.

[0045] Thermal energy from the heater member 16 may be coupled to thedie 31 alone, the die 31 and the output end 27 of the guide tube 25 orthe die 31 and any desired portion of the guide tube 25. Also, it may beuseful in some embodiments to generate a temperature gradient along thecentering insert 34, die 31 and guide tube 25. In one embodiment, it ispreferable to concentrate most of the thermal energy on the die 31 andoutput end 27 of the guide tube 25.

[0046] As thermal energy is transferred to the extrudable polymercartridge 57, it can begin to soften or melt at a melt zone 57A. Whenthe portion of the extrudable polymer cartridge 57 adjacent the die 31approaches a desired temperature or viscosity or both, force in thedirection of extrusion is applied to the extrudable polymer cartridge57. This pushes the melted or softened polymer material in the melt zone57A of the extrudable polymer cartridge 57 into the input end 32 andinner lumen 44 of the die 31 and onto the elongate intracorporeal device12. When the force in the direction of extrusion is initiated on theextrudable polymer cartridge 57, the elongate intracorporeal device 12is simultaneously advanced in the direction of extrusion so that as theextrudable polymer cartridge 57 is heated, melted, and forced into thedie 31. The melted extrudable polymer cartridge 57 is applied to themoving elongate intracorporeal device 12 in a radially inward directionas indicated by arrows 57B. As shown in FIG. 2, the extrudable polymercartridge 57 is applied evenly at the melt zone 57A from all directionsas indicated by arrows 57B. The evenly distributed inward radial forcehelps maintain the concentricity of the polymer coating 11 if the lumenof the extrudable polymer cartridge is concentric with the longitudinalaxis 64 of the extrudable polymer cartridge 57 and longitudinal axis 43of the die 31. The coating process is carried out continuously until adesired portion of the elongate intracorporeal device 12 has beencoated. The process may be terminated by exhaustion of the extrudablepolymer cartridge 57, cessation of the force in the direction ofextrusion on the extrudable polymer cartridge, or passage of anextremity 76 of the elongate intracorporeal device 12 through the die31.

[0047] In the embodiment of the polymer coating apparatus 10 shown inFIGS. 14, the force in the direction of extrusion on the extrudablepolymer cartridge 57 is applied by the contact end 55 of the push tube53 which is mechanically coupled to the push tube actuator 52 Onealternative to using push tube actuator motor 66 to apply force andmotion to the push tube actuator 52 is to apply a substantially constantforce in the direction of extrusion on the push tube actuator 52 with anoptional constant force spring 77. The constant force spring 77 may besecured to any suitable portion of the push tube 53, push tube actuator52, guide tube assembly mount 14, or mounting surface 15. A suitabletrigger mechanism can be used to initiate the force from the constantforce spring 77 in the direction of extrusion at the appropriate time inthe coating cycle.

[0048] When the coating cycle is finished, the elongate intracorporealdevice 12 is removed from the guide tube assembly 13 and the puller 40.The retainer cap 24 of the guide tube housing 17 is removed as well asthe spent die 31, centering insert 34, guide tube 25 and extrudablepolymer cartridge 57. The push tube 53 is then reset to its originalposition and a new guide tube 25, extrudable polymer cartridge 57, die31 and centering insert 34 loaded into the guide tube housing 17. It maybe possible to reuse the die 31, guide tube 25 or centering insert 34.Also, the new guide tube 25, die 31 and extrudable polymer cartridge 57may be loaded into the guide tube housing 17 in one connected modularunit or subassembly in order to lessen the time between coating cycles.

[0049] The temperature range of the heater member 16, die 31 and desiredportion of the guide tube 25 used for the process of the polymer coatingapparatus 10 can vary significantly depending on the desired result,size and material composition of the elongate intracorporeal device 12and material composition of the extrudable polymer cartridge 57. Forcoating an elongate intracorporeal device 12 consisting of a guidewire,in order to yield a finished outer diameter of about 0.012 to about0.016 inch, a temperature range of about 340 to about 390 degreesFahrenheit, specifically about 350 to about 380 degrees Fahrenheit istypical if using polyurethane for the extrudable polymer cartridge 57material.

[0050] As the temperature of the heater member 16 is changing as thecoating process is started, it may be desirable to trigger axialmovement of the elongate intracorporeal device 12 in the direction ofextrusion just prior to reaching the desired target temperature. Forexample, if the ultimate target temperature of the heater member 16 isabout 365 degrees Fahrenheit, then the puller 40 may be triggered byprogramming of the computer 71 to start the puller 40 moving in thedirection of extrusion when the heater member 16 reaches a temperatureof about 362 degrees Fahrenheit.

[0051] The rate of speed of pull of the elongate intracorporeal device12 through the guide tube assembly 13 can vary considerably depending onmany factors including the size and durability of the elongateintracorporeal device 12, the temperature of the heater member 16 andthe material of the extrudable polymer cartridge 57. For the examplegiven above, with an elongate intracorporeal device 12 of stainlesssteel having a desired finish outer diameter of about 0.012 to about0.016 inch, using polyurethane for the extrudable polymer cartridge 57,a typical rate of pull can be from about 0.25 to about 1.0 cm/second fordurable portions of the member 12, and about 0.05 to about 0.15cm/second for more fragile portions of the member 12, such as portionsof the elongate intracorporeal device 12 covered by a helical coil whichis subject to mechanical deformation. In one embodiment, the forceapplied to the extrudable polymer cartridge 57 by the push tube 53 viathe push tube actuator 52 can be from about 0.5 to about 10 pounds,specifically about 1.0 to about 2.0 pounds.

[0052] In another embodiment, the cartridge advancement mechanism 51,described above as consisting of a push tube actuator 52 coupled to apush tube 53 can be replaced with a substantially constant force springcoupled to the push tube so as to apply a substantially constant forcein the direction of extrusion on the extrudable polymer cartridge 57during the coating process. The amount of force can be similar to theforces noted above with regard to the push tube actuator 52 embodiment.

[0053] FIGS. 5-6C illustrate an enlarged view of the embodiment of thedie 31 shown in FIGS. 2 and 4. The die 31 can be made from a variety ofmaterials, including high temperature polymers such as PI, PTFE, LCP andPEEK. The die 31 can also be made from metal or any other suitablematerial The die 31 has an input end 32, an output end 33 and an innerlumen 44 An extrusion orifice 68 is disposed at an output extremity 78of the inner lumen 44. The length 79 of the inner lumen 44 of the die 31can vary significantly depending on the desired result and numerousother factors. In one embodiment, the length of the inner lumen 44 canrange from about 0.02 to about 0.5 inch, specifically about 0.05 toabout 0.08 inch. A transverse dimension of the inner lumen 44 andextrusion orifice 68 of the die 31 in said embodiment can be from about0.01 to about 0.25 inch, specifically about 0.011 to about 0.015 inch.

[0054] The die 31 has an outer transverse dimension similar to an outertransverse dimension of the guide tube 25. An input taper 81 at theinput end 32 of the die 31 has an input taper angle 82. An optionaloutput taper 83 at the output end 33 of the die 31 has an output taperangle 84. Output taper angle 84 and input taper angle 82 can be fromabout 15 degrees to about 180 degrees, i.e. a flat cut end with notaper, specifically, from about 35 to about 45 degrees, and morespecifically, from about 36 to about 40 degrees. Although the extrusionorifice 68 of the die 31 shown in FIG. 5 has a round cross section asshown in FIG. 6A, the cross section of the extrusion orifice 68 can haveany desired configuration or shape such as the square configurationshown in FIG. 6B or the elliptical configuration shown in FIG. 6C. Anyother suitable extrusion orifice 68 configuration or cross sectionalshape can be used to achieve a desired result.

[0055]FIG. 7 illustrates a tandem polymer coating apparatus 86 having afirst polymer coating apparatus 87 in line with a second polymer coatingapparatus 88. The various components of the first and second polymercoating apparatus 87 and 88 can have components similar to thecomponents of the polymer coating apparatus 10 of FIGS. 1-4, and arenumbered accordingly. A single puller 89 can be used for the tandempolymer coating apparatus 86 . By using a tandem coating apparatus 86,multiple layers of polymer coating may be applied to a single elongateintracorporeal device 12 by drawing the elongate intracorporeal device12 through the first and second polymer coating apparatus 87 and 88 inserial in a direction of extrusion indicated by arrow 91. Multiplecoatings may be applied so as to be axially coextensive on the elongateintracorporeal device 12. Multiple coatings may also be applied toseparate axial portions of an elongate intracorporeal device 12 or suchthat the multiple coatings overlap each other by a desired amount.Although FIG. 7 depicts a tandem coating apparatus 86 having two polymercoating apparatus 87 and 88 in serial, any desired number of polymercoating apparatus may be used.

[0056]FIGS. 8 and 9 illustrate another embodiment of a guide tubeassembly 95 having features of the invention. The guide tube assembly 95includes a guide tube 96 having an input end 97 and an output end 98disposed partially within a guide tube housing 101. The guide tube 96can be made from a variety of polymer materials, specifically, hightemperature polymer materials such as PI, PTFE, LCP and PEEK The guidetube housing 101 has an input end 102 and an output end 103 The guidetube housing 101 also has a central inner lumen 104 which is configuredto accept the guide tube 96. The central inner lumen 104 of the guidetube housing 101 has a retainer lip 105 at the input end 102 of theguide tube housing 101 which is configured to prevent the guide tube 96from exiting the input end 102 of the guide tube housing 101 withoutblocking or interfering with a guide chamber 106 disposed within theguide tube 96. The central inner lumen 104 of the guide tube housing 101is capped at the output end 103 with a retainer cap 107. The retainercap 107 has a retainer cap top 108, a threaded portion 109 and aretainer cap insert 112. The retainer cap 107, when secured to the guidetube housing 101, confines the output end 98 of the guide tube 96 withinthe central inner lumen 104 of the guide tube housing 101.

[0057] Disposed within the output end 98 of the guide tube 96 is a die113 which has an input end 114 and an output end 115 and which can havethe same configuration, dimensions and materials as the die 31 shown inFIGS. 5-6C. Disposed within the guide tube 96 adjacent the input end 114of the die 113 is an extrudable polymer cartridge 116 having an inputend 117 and an output end 118. An inner lumen 121 extends along alongitudinal axis 122 of the extrudable polymer cartridge 116. A pushtube 123 having a contact end 124 and an actuator end 125 is disposedwithin a guide chamber 126 of the guide tube 96 with the contact end 124adjacent the input end 117 of the extrudable polymer cartridge 116 Apush tube actuator rod 127 with an actuator rod tip 128 is disposedpartially within the guide chamber 126 with the actuator rod tip 128disposed adjacent the actuator end 125 of the push tube 123.

[0058] A heater member 131 is disposed within the guide tube housing 101about the output end 98 of the guide tube 96. The heater member 131 hasa heater member housing 132, heater rods 133 and heater lead wires 134which supply power to the heater rods 133. The heater member housing 132can be made from stainless steel or any other suitable material whichcan withstand high temperatures. It may be desirable to use a materialwhich readily conducts heat for the heater member housing 132. Theheater member 131 is held in place within the guide tube housing 101 bya guide tube housing cap 135 disposed at the output end 103 of the guidetube housing 101.

[0059] The guide tube housing cap 135 can be secured to the guide tubehousing 101 by screws 136. The guide tube housing 101 has cooling airchannels 137 disposed within the housing 101 fed by air lines 138 toallow air to be circulated about the heater member 131 and cool theheater member 131 after a polymer coating process has been completed.Thereafter, a new guide tube 96, die 113, extrudable polymer cartridge116 and push tube 123 can be inserted into the guide tube assembly 95.The optionally disposable components of the guide tube assembly 95including the guide tube 96, die 113, extrudable polymer cartridge 116and push tube 123 may be replaced separately, or all at once as amodular subassembly.

[0060] The guide tube 96, die 113, extrudable polymer cartridge 116 andpush tube 123 are replaced by removing the retainer cap 107, withdrawingthe spent guide tube 96, die 113, extrudable polymer cartridge 116 andpush tube 123, and then replacing a new guide tube, die, extrudablepolymer cartridge and push tube. The retainer cap 107 is then secured tothe guide tube housing 101. The guide tube housing 101, guide tubehousing cap 135 and retainer cap top 108 can all be made from a highstrength machineable polymer insulator, such as Vespel® which is apolyimide resin based composite, or any other suitable material. Aninsulative material can be used for the guide tube housing 101, guidetube housing cap 135 and retainer cap top 108 in order to facilitatehandling by the operators of the device who must handle the variouscomponents of the polymer coating apparatus during its operation.

[0061] The guide tube assembly 95 shown in FIGS. 8 and 9 is used in amanner similar to that discussed above with regard to the embodiment ofthe guide tube assembly 13 shown in FIGS. 14. The coating processparameters discussed above with regard to the embodiment of the guidetube assembly 13 shown in FIGS. 1-4, including, but not limited to,temperatures, pull speeds, rates of feed, forces on the extrudablepolymer cartridge 57, and the like, and structures and alternativestructures used to implement those parameters, can all be the same orsimilar for the embodiment of the guide tube assembly 95 shown in FIGS.8 and 9.

[0062] FIGS. 10-19 illustrate various configurations of extrudablepolymer cartridges having features of the invention. Specifically, FIGS.10 and 11 illustrate an extrudable polymer cartridge 141 having an inputend 142, an output end 143 , and a plurality of longitudinal segments144 which may be made of polymers having different compositions. Polymercomposition of the longitudinal segments 144 may vary in material type,shore hardness, color, radiopaque doping concentrations and the like. Aninner lumen 145 extends from the input end 142 to the output end, 143and is concentric with a longitudinal axis 145A of the extrudablepolymer cartridge 141. The extrudable polymer cartridge 141 can bemolded with the longitudinal segments 144 molded into place adjacenteach other. Alternatively, the longitudinal segments 144 could be moldedor extruded separately, and subsequently bonded or fused together. Also,the longitudinal segments 144 could be molded or extruded separately andput into a guide chamber 28 or 126 of the invention without being bondedor fused together.

[0063] As used herein, the term polymer, as used with regard to polymercoatings, cartridges and the like, is intended to be interpreted broadlyand include all polymers, prepolymers and the like which are suitablefor use as a coating of an elongate intracorporeal device. Somematerials suitable for the extrudable polymer cartridge 141, and allextrudable polymer cartridges discussed herein, can includepolyurethanes, including polyurethane thermoplastic elastomers;polyamides (nylons); polyethers; polyesters-, polyacetals; acrylics;methacrylics; cellulosics; fluoropolastics; epoxies; keton-based basedresins and polymers; polyimide based resins and polymers; bismaleimides;nitriles; polyarylates; polycarbonates; liquid crystal polymers;terephthalate resins and polymers including polybutylene terephthalateand polyethylene terephthalate; polyetherimides; polyolefins includingpolyethylenes, polypropylenes, polybutylenes, polybutadienes; polyvinylsincluding polystyrenes and polyvinyl chlorides; elastomers especiallythermoplastic elastomers; silicones; rubbers; ionomers; ceramers;dendritic polymers; and derivatives, copolymers, multipolymers, blendsand/or mixtures of any of the previous listed resins and polymers withineach group and between each group. This latter includes polyether blockamide elastomers such as COPA and PEBAX.

[0064] Any of the aforementioned polymers may be loaded with additivesto control the physical properties such as flexural modulus, hardness,and radiopacity. The shore hardness of an embodiment of extrudablepolymer cartridge 141 and embodiments of other extrudable polymercartridges discussed herein can range from about 50A to about 55D,preferably about 80A to about 50D, and more preferably about 85A toabout 95A.

[0065]FIGS. 12 and 13 show an extrudable polymer cartridge 146 having aninput end 147, an output end 148, a first lateral segment 149 and asecond lateral segment 150. An inner lumen 151 extends from the inputend 147 to the output end 148 and is concentrically located within theextrudable polymer cartridge 146. The extrudable polymer cartridge 146can be formed by molding or extruding the cartridge 146 in its finalform. In addition, the first and second lateral segments 149 and 150could be formed independently and then fused or bonded together, orplaced within a guide chamber 28 or 126 of the invention togetherwithout being fused or bonded together.

[0066]FIGS. 14 and 15 illustrate an extrudable polymer cartridge 153having an input end 154 and an output end 155 with an inner lumen 156extending from the input end 154 to the output end 155. The inner lumen156 has a longitudinal axis 157 which is substantially parallel to alongitudinal axis 158 of the extrudable polymer cartridge 153 andlaterally offset from the longitudinal axis 158 of the extrudablepolymer cartridge 153.

[0067]FIGS. 16 and 17 show an extrudable polymer cartridge 161 having aninput end 162 and an output end 162. The extrudable polymer cartridge161 has a first concentric layer 164 and a second concentric layer 165disposed about the first concentric layer 164 . An inner lumen 166extends from the input end 162 to the output end 163 and is disposedconcentrically within the extrudable polymer cartridge 161. The firstconcentric layer 164 may have a different polymer composition from thesecond concentric layer 165.

[0068]FIGS. 18 and 19 show an extrudable polymer cartridge 167 having aninput end 168 and an output end 169. A first inner lumen 170 extendsfrom the input end 168 to the output end 169 which may be disposedsubstantially concentric within the extrudable polymer cartridge 167 andwhich is substantially parallel to a longitudinal axis 171 of theextrudable polymer cartridge. A second inner lumen 172 extends from theinput end 168 to the output end 169 and is also substantially parallelto the longitudinal axis 171 of the extrudable polymer cartridge 167.The second inner lumen 172 has a longitudinal axis 173 which is offsetfrom the longitudinal axis 171 of the extrudable polymer cartridge 167.The first inner lumen 170 would can encompass an elongate intracorporealdevice during an extrusion process. The second inner lumen 172 could beused to encompass a secondary elongate element such as a wire,fiberoptic, small diameter tubing or the like. The use of such anextrudable polymer cartridge 167 would facilitate application of apolymer coating to a plurality of elongate members which could be drawnthrough guide chambers 28 or 126 and extrusion orifice 68 during acoating process.

[0069] Unless otherwise described herein, conventional materials andmanufacturing methods may be used to make the guiding members of thepresent invention. Additionally, various modifications may be made tothe present invention without departing from the scope thereof. Whileparticular forms of the invention have been illustrated and described,it will be apparent that various modifications can be made withoutdeparting from the spirit and scope of the invention. Accordingly, it isnot intended that the invention be limited, except as by the appendedclaims.

What is claimed is:
 1. An apparatus for applying a polymer coating to anelongate intracorporeal device comprising: a guide tube having a guidechamber disposed therein, an input end with an input port in fluidcommunication with the guide chamber, and an output end; a die disposedat the output end of the guide tube having an extrusion orifice in fluidcommunication with the guide chamber; a heater member in thermalcommunication with the guide tube; and a push tube slidably disposedwithin the guide chamber having a contact end, an attachment end, alongitudinal axis and at least one inner lumen disposed substantiallyparallel to the longitudinal axis which is configured to accept theelongate intracorporeal device.
 2. The apparatus of claim 1 furthercomprising an extrudable polymer cartridge disposed within the guidechamber between the contact end of the push tube and the die.
 3. Theapparatus of claim 1 further comprising a puller disposed adjacent theoutput end of the guide tube which is configured to be temporarilysecured to the elongate intracorporeal device and draw the elongateintracorporeal device through the guide chamber and extrusion orifice.4. The apparatus of claim 3 further comprising a push tube actuatorwhich is disposed adjacent the input end of the guide tube andconfigured to translate linearly in the direction of extrusion forapplying an axial force to the push tube which is then imparted by thecontact end of the push tube to the extrudable polymer cartridge.
 5. Theapparatus of claim 4 further comprising a computing machine which iselectronically connected to at least one temperature sensor coupled tothe heater member, the puller, and the push tube actuator and which isconfigured to repeatably and simultaneously control the temperature ofthe output end of the guide chamber, the force applied to and the feedrate of the polymer cartridge and the rate of pull of the elongateintracorporeal device through the extrusion orifice.
 6. The apparatus ofclaim 1 wherein the die is comprised of a polymer.
 7. The apparatus ofclaim 6 wherein the die comprises a polymer selected from the groupconsisting of PI, PTFE, LCP and PEEK.
 8. The apparatus of claim 1wherein the guide tube is comprised of a polymer.
 9. The apparatus ofclaim 8 wherein the guide tube comprises a polymer selected from thegroup consisting of PI, PTFE, LCP and PEEK.
 10. An apparatus forapplying a polymer coating to an elongate intracorporeal devicecomprising: a guide chamber having an input end with an input port andan output end; an extrusion orifice disposed at the output end of theguide chamber in fluid communication with the guide chamber; a heatermember in thermal communication with the guide chamber; and a cartridgeadvancement mechanism disposed adjacent the guide chamber.
 11. Theapparatus of claim 10 further comprising an extrudable polymer cartridgeat least partially disposed within the guide chamber mechanicallycoupled to the cartridge advancement mechanism and having a lumenextending longitudinally through the cartridge which is configured toslidingly accept the elongate intracorporeal device and which isdisposed substantially concentric to a longitudinal axis of theextrudable polymer cartridge.
 12. The apparatus of claim 10 wherein theguide chamber is formed by a guide tube having an input end with aninput port and an output end.
 13. The apparatus of claim 10 wherein thecartridge advancement mechanism comprises a push tube disposed withinthe guide chamber and coupled to a push tube actuator which isconfigured to translate linearly and impart axial movement on theextrudable polymer cartridge in the direction of extrusion.
 14. Theapparatus of claim 10 wherein the guide chamber tapers to a reducedtransverse inner dimension in a direction of extrusion at the output endof the guide chamber.
 15. The apparatus of claim 10, further comprisinga puller disposed adjacent the output end of the guide chamber which isconfigured to be temporarily secured to the elongate intracorporealdevice and draw the elongate intracorporeal device through the guidechamber and extrusion orifice.
 16. The apparatus of claim 10 wherein theheater member is configured-to create a desired temperature gradient inan axial direction along the guide chamber with a higher temperature atthe output end relative to the temperature at the input end.
 17. Theapparatus of claim 11 wherein the extrudable polymer cartridge comprisesa plurality of longitudinal segments with at least two of thelongitudinal segments being made of different polymer compositions. 18.The apparatus of claim 11 wherein the extrudable polymer cartridgecomprises at least two lateral segments having different polymercompositions.
 19. The apparatus of claim 11 wherein the extrudablepolymer cartridge comprises at least two concentric layers havingdifferent polymer compositions.
 20. A method for applying a polymercoating to an elongate intracorporeal device comprising: a) providing anapparatus for applying a polymer coating to an elongate intracorporealdevice comprising: a guide chamber having an input end with an inputport and an output end, an extrusion orifice disposed at the output endof the guide chamber in fluid communication with the guide chamber, aheater member in thermal communication with the guide chamber, and acartridge advancement mechanism disposed adjacent the guide chamber; b)placing an extrudable polymer cartridge into the guide chamber; c)placing the elongate intracorporeal device through the extrusion orificeand at least a portion of the extrudable polymer cartridge; and d)activating the heater member to heat the extrudable polymer cartridgeand soften it adjacent the extrusion orifice and translating theelongate intracorporeal device in a direction of extrusion whileapplying a force in the direction of extrusion on the extrudable polymercartridge with the cartridge advancement mechanism.
 21. The method ofclaim 20 wherein heater member is disposed at the output end of theguide chamber.
 22. The method of claim 20 wherein the guide chambertapers to a reduced transverse inner dimension in the direction ofextrusion at the output end of the guide chamber.
 23. The method ofclaim 20 wherein cartridge advancement mechanism comprises a push tubedisposed within the guide chamber and coupled to a push tube actuatorwhich is configured to translate linearly and impart axial movement onthe extrudable polymer cartridge in the direction of extrusion.
 24. Themethod of claim 20 wherein the apparatus for applying a polymer coatingto an elongate intracorporeal device further comprises a puller disposedadjacent the output end of the guide chamber which is configured to betemporarily secured to the elongate intracorporeal device and draw theelongate intracorporeal device through the guide chamber and extrusionorifice.
 25. The method of claim 20 wherein the apparatus for applying apolymer coating to an elongate intracorporeal device further comprises acomputing machine which is electronically connected to at least onetemperature sensor coupled to the heater member, the puller, and thepush tube actuator and further comprising simultaneously controlling thetemperature of the output end of the guide chamber, the force applied toand the feed rate of the polymer cartridge and the rate of pull of theelongate intracorporeal device through the extrusion orifice.